Moving along nicely! The tall, pointy, little fin design makes it look fast sitting still. I am sure it will look extra fast while it is Binary Effusing.
It's too late for this build, but an option for holding a rail button without a ring is to take a rectangle (1" x 2" -ish) of 1/4" balsa, sand that to the inner contour of the tube, put a T-nut through the balsa in the center (grind if necessary so it doesn't stick out), epoxy T-nut in place on balsa, CA seal the flat side for strength, drill hole in airframe, epoxy balsa block in place using a greased screw to hold it in the right place while the epoxy sets. Sounds long, but it takes <1 h total with 5 min epoxy. This gives you a big epoxy/CA soaked balsa backer block. As an added bonus the railbutton is removable. Also, if it will be fore of the top CR you can easily sand a taper into the bottom and top of the block so they don't snag the parachute or cord, this is how I use them.
NOTE: I may have ripped this method off from one of your threads, rendering this advice completely useless to you...You, Paul, and a few other prolific builders on here have influenced my methods so much I don't know where the borders are anymore, so if I am ripping you (or someone else) off no harm was intended.
Keep going Captain, it's lookin good!
